今天我们尝试Kotlin整合Vertx，并决定建立一个非常简单的Web应用程序，使用Kotlin和Vertx作为编程语言进行编码构建。

生成项目

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打开控制台窗口执行以下代码进行生成一个maven项目

mvn archetype:generate -DgroupId=com.edurt.kvi -DartifactId=kotlin-vertx-integration -DarchetypeArtifactId=maven-archetype-quickstart -Dversion=1.0.0 -DinteractiveMode=false

修改pom.xml增加java和kotlin的支持

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">

    <modelVersion>4.0.0</modelVersion>
    <groupId>com.edurt.kvi</groupId>
    <artifactId>kotlin-vertx-integration</artifactId>
    <packaging>jar</packaging>
    <version>1.0.0</version>

    <name>kotlin-vertx-integration</name>
    <description>Kotlin Vertx Integration is a open source kotlin vertx integration example.</description>

    <!-- properties -->
    <properties>
        <!-- dependency -->
        <dependency.kotlin.version>1.2.71</dependency.kotlin.version>
        <dependency.vertx.ersion>3.4.1</dependency.vertx.ersion>
        <!-- plugin -->
        <plugin.maven.compiler.version>3.3</plugin.maven.compiler.version>
        <plugin.maven.javadoc.version>2.10.4</plugin.maven.javadoc.version>
        <plugin.maven.kotlin.version>1.2.71</plugin.maven.kotlin.version>
        <!-- environment -->
        <environment.compile.java.version>1.8</environment.compile.java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <jvmTarget>1.8</jvmTarget>
    </properties>

    <!-- dependencys -->
    <dependencies>
        <!-- kotlin -->
        <dependency>
            <groupId>org.jetbrains.kotlin</groupId>
            <artifactId>kotlin-stdlib-jdk8</artifactId>
            <version>${dependency.kotlin.version}</version>
        </dependency>
        <dependency>
            <groupId>org.jetbrains.kotlin</groupId>
            <artifactId>kotlin-reflect</artifactId>
            <version>${dependency.kotlin.version}</version>
        </dependency>
        <!-- vertx -->
        <dependency>
            <groupId>io.vertx</groupId>
            <artifactId>vertx-core</artifactId>
            <version>${dependency.vertx.ersion}</version>
        </dependency>
        <dependency>
            <groupId>io.vertx</groupId>
            <artifactId>vertx-web</artifactId>
            <version>${dependency.vertx.ersion}</version>
        </dependency>
    </dependencies>

    <!-- prerequisites -->
    <prerequisites>
        <maven>3.5.0</maven>
    </prerequisites>

    <!-- build -->
    <build>
        <sourceDirectory>${project.basedir}/src/main/kotlin</sourceDirectory>
        <testSourceDirectory>${project.basedir}/src/test/kotlin</testSourceDirectory>
        <plugins>
            <plugin>
                <artifactId>kotlin-maven-plugin</artifactId>
                <groupId>org.jetbrains.kotlin</groupId>
                <configuration>
                    <args>
                        <arg>-Xjsr305=strict</arg>
                    </args>
                    <compilerPlugins>
                        <plugin>spring</plugin>
                        <plugin>jpa</plugin>
                        <plugin>all-open</plugin>
                    </compilerPlugins>
                    <pluginOptions>
                        <option>all-open:annotation=javax.persistence.Entity</option>
                    </pluginOptions>
                </configuration>
                <dependencies>
                    <dependency>
                        <groupId>org.jetbrains.kotlin</groupId>
                        <artifactId>kotlin-maven-allopen</artifactId>
                        <version>${plugin.maven.kotlin.version}</version>
                    </dependency>
                    <dependency>
                        <groupId>org.jetbrains.kotlin</groupId>
                        <artifactId>kotlin-maven-noarg</artifactId>
                        <version>${plugin.maven.kotlin.version}</version>
                    </dependency>
                </dependencies>
                <executions>
                    <execution>
                        <id>kapt</id>
                        <goals>
                            <goal>kapt</goal>
                        </goals>
                        <configuration>
                            <sourceDirs>
                                <sourceDir>src/main/kotlin</sourceDir>
                            </sourceDirs>
                            <annotationProcessorPaths>
                                <annotationProcessorPath>
                                    <groupId>org.springframework.boot</groupId>
                                    <artifactId>spring-boot-configuration-processor</artifactId>
                                    <version>${project.parent.version}</version>
                                </annotationProcessorPath>
                            </annotationProcessorPaths>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>${plugin.maven.compiler.version}</version>
                <configuration>
                    <source>${environment.compile.java.version}</source>
                    <target>${environment.compile.java.version}</target>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-javadoc-plugin</artifactId>
                <version>${plugin.maven.javadoc.version}</version>
                <configuration>
                    <aggregate>true</aggregate>
                    <!-- custom tags -->
                    <tags>
                        <tag>
                            <name>Description</name>
                            <placement>test</placement>
                            <head>description</head>
                        </tag>
                    </tags>
                    <!-- close jdoclint check document -->
                    <additionalparam>-Xdoclint:none</additionalparam>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

添加Vertx实例

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创建CoreVerticle类文件

package com.edurt.kvi.core

import io.vertx.core.AbstractVerticle
import io.vertx.core.Future
import io.vertx.core.Handler
import io.vertx.ext.web.Router
import io.vertx.ext.web.RoutingContext

class CoreVerticle : AbstractVerticle() {

    override fun start(startFuture: Future<Void>?) {
        val router = createRouter()
        val port = config().getInteger("http.port", 8080)
        vertx.createHttpServer()
                .requestHandler { router.accept(it) }
                .listen(port) { result ->
                    if (result.succeeded()) {
                        startFuture?.complete()
                    } else {
                        startFuture?.fail(result.cause())
                    }
                }
    }

    private fun createRouter() = Router.router(vertx).apply {
        get("/").handler(handlerRoot)
    }

    /**
     * create router instance
     */
    val handlerRoot = Handler<RoutingContext> { req ->
        req.response().end("Hello Kotlin Vertx Integration!")
    }

}

设置启动类

package com.edurt.kvi

import com.edurt.kvi.core.CoreVerticle
import io.vertx.core.Vertx

class KotlinVertxIntegration

fun main(args: Array<String>) {
    val vertx = Vertx.vertx()
    vertx.deployVerticle(CoreVerticle::class.java.name)
}

以上操作在vertx.deployVerticle阶段执行了部署Verticle的操作，即部署CoreVerticle。

启动应用后浏览器访问http://localhost:8080出现以下页面

增加页面渲染功能

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修改pom.xml文件增加页面依赖

<dependency.slf4j.version>1.7.25</dependency.slf4j.version>

<dependency>
    <groupId>io.vertx</groupId>
    <artifactId>vertx-web-templ-thymeleaf</artifactId>
    <version>${dependency.vertx.ersion}</version>
</dependency>
<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-log4j12</artifactId>
    <version>${dependency.slf4j.version}</version>
</dependency>

增加页面渲染文件

package com.edurt.kvi.router

import io.vertx.ext.web.Router
import io.vertx.ext.web.RoutingContext
import io.vertx.ext.web.templ.ThymeleafTemplateEngine
import org.thymeleaf.templatemode.TemplateMode

class HomeViewRouter

fun index(r: Router) {
    val engine = ThymeleafTemplateEngine.create().setMode(TemplateMode.HTML)
    r.get("/index.html").handler { c ->
        render(c, engine, "templates/index.html")
    }
}

fun render(c: RoutingContext, engine: ThymeleafTemplateEngine, templ: String) {
    engine.render(c, templ) { res ->
        if (res.succeeded()) {
            c.response().end(res.result())
        } else {
            c.fail(res.cause())
        }
    }
}

在templates/index.html目录下创建页面文件

<!DOCTYPE html SYSTEM "http://www.thymeleaf.org/dtd/xhtml1-strict-thymeleaf-4.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title>Kotlin Vertx Integration</title>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
</head>

<body>
<p>Welcome To Kotlin Vertx Integration!</p>
</body>
</html>

修改CoreVerticle增加页面跳转

package com.edurt.kvi.core

import com.edurt.kvi.router.index
import io.vertx.core.AbstractVerticle
import io.vertx.core.Future
import io.vertx.core.Handler
import io.vertx.core.Vertx
import io.vertx.core.http.HttpServerResponse
import io.vertx.ext.web.Router
import io.vertx.ext.web.RoutingContext

class CoreVerticle : AbstractVerticle() {

    override fun start() {
        val router = createRouter(vertx)

        // go to index page
        index(router)

        vertx.createHttpServer().requestHandler { handler -> router.accept(handler) }.listen(8080)

//        val port = config().getInteger("http.port", 8080)
//        vertx.createHttpServer()
//                .requestHandler { router.accept(it) }
//                .listen(port) { result ->
//                    if (result.succeeded()) {
//                        startFuture?.complete()
//                    } else {
//                        startFuture?.fail(result.cause())
//                    }
//                }
    }

    private fun createRouter() = Router.router(vertx).apply {
        get("/").handler(handlerRoot)
    }

    /**
     * create router instance
     */
    val handlerRoot = Handler<RoutingContext> { req ->
        req.response().end("Hello Kotlin Vertx Integration!")
    }

    fun createRouter(v: Vertx): Router {
        var router = Router.router(v)
        router.route("/").handler { c -> c.response().end("Hello Kotlin Vertx Integration!") }
        router.route("/index").handler { c -> c.response().html().end("Hello Kotlin Vertx Integration Page!") }
        return router
    }

    fun HttpServerResponse.html(): HttpServerResponse {
        return this.putHeader("content-type", "text/html")
    }

}

启动应用后浏览器访问http://localhost:8080/index.html出现以下页面